networking/libiproute/iprule.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * iprule.c             "ip rule".
   4  *
   5  *              This program is free software; you can redistribute it and/or
   6  *              modify it under the terms of the GNU General Public License
   7  *              as published by the Free Software Foundation; either version
   8  *              2 of the License, or (at your option) any later version.
   9  *
  10  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  11  *
  12  *
  13  * Changes:
  14  *
  15  * Rani Assaf <rani@magic.metawire.com> 980929: resolve addresses
  16  * initially integrated into busybox by Bernhard Fischer
  17  */
  18
  19 #include "libbb.h"
  20 #include <syslog.h>
  21 #include <sys/socket.h>
  22 #include <netinet/in.h>
  23 #include <netinet/ip.h>
  24 #include <arpa/inet.h>
  25
  26 #include "rt_names.h"
  27 #include "utils.h"
  28 #include "ip_common.h"
  29 /*
  30 static void usage(void) __attribute__((noreturn));
  31
  32 static void usage(void)
  33 {
  34         fprintf(stderr, "Usage: ip rule [ list | add | del ] SELECTOR ACTION\n");
  35         fprintf(stderr, "SELECTOR := [ from PREFIX ] [ to PREFIX ] [ tos TOS ] [ fwmark FWMARK ]\n");
  36         fprintf(stderr, "            [ dev STRING ] [ pref NUMBER ]\n");
  37         fprintf(stderr, "ACTION := [ table TABLE_ID ] [ nat ADDRESS ]\n");
  38         fprintf(stderr, "          [ prohibit | reject | unreachable ]\n");
  39         fprintf(stderr, "          [ realms [SRCREALM/]DSTREALM ]\n");
  40         fprintf(stderr, "TABLE_ID := [ local | main | default | NUMBER ]\n");
  41         exit(-1);
  42 }
  43 */
  44 static int print_rule(struct sockaddr_nl *who ATTRIBUTE_UNUSED,
  45                                         struct nlmsghdr *n, void *arg)
  46 {
  47         FILE *fp = (FILE*)arg;
  48         struct rtmsg *r = NLMSG_DATA(n);
  49         int len = n->nlmsg_len;
  50         int host_len = -1;
  51         struct rtattr * tb[RTA_MAX+1];
  52         char abuf[256];
  53         SPRINT_BUF(b1);
  54
  55         if (n->nlmsg_type != RTM_NEWRULE)
  56                 return 0;
  57
  58         len -= NLMSG_LENGTH(sizeof(*r));
  59         if (len < 0)
  60                 return -1;
  61
  62         memset(tb, 0, sizeof(tb));
  63         parse_rtattr(tb, RTA_MAX, RTM_RTA(r), len);
  64
  65         if (r->rtm_family == AF_INET)
  66                 host_len = 32;
  67         else if (r->rtm_family == AF_INET6)
  68                 host_len = 128;
  69 /*      else if (r->rtm_family == AF_DECnet)
  70                 host_len = 16;
  71         else if (r->rtm_family == AF_IPX)
  72                 host_len = 80;
  73 */
  74         if (tb[RTA_PRIORITY])
  75                 fprintf(fp, "%u:\t", *(unsigned*)RTA_DATA(tb[RTA_PRIORITY]));
  76         else
  77                 fprintf(fp, "0:\t");
  78
  79         fprintf(fp, "from ");
  80         if (tb[RTA_SRC]) {
  81                 if (r->rtm_src_len != host_len) {
  82                         fprintf(fp, "%s/%u", rt_addr_n2a(r->rtm_family,
  83                                                          RTA_PAYLOAD(tb[RTA_SRC]),
  84                                                          RTA_DATA(tb[RTA_SRC]),
  85                                                          abuf, sizeof(abuf)),
  86                                 r->rtm_src_len
  87                                 );
  88                 } else {
  89                         fprintf(fp, "%s", format_host(r->rtm_family,
  90                                                        RTA_PAYLOAD(tb[RTA_SRC]),
  91                                                        RTA_DATA(tb[RTA_SRC]),
  92                                                        abuf, sizeof(abuf))
  93                                 );
  94                 }
  95         } else if (r->rtm_src_len) {
  96                 fprintf(fp, "0/%d", r->rtm_src_len);
  97         } else {
  98                 fprintf(fp, "all");
  99         }
 100         fprintf(fp, " ");
 101
 102         if (tb[RTA_DST]) {
 103                 if (r->rtm_dst_len != host_len) {
 104                         fprintf(fp, "to %s/%u ", rt_addr_n2a(r->rtm_family,
 105                                                          RTA_PAYLOAD(tb[RTA_DST]),
 106                                                          RTA_DATA(tb[RTA_DST]),
 107                                                          abuf, sizeof(abuf)),
 108                                 r->rtm_dst_len
 109                                 );
 110                 } else {
 111                         fprintf(fp, "to %s ", format_host(r->rtm_family,
 112                                                        RTA_PAYLOAD(tb[RTA_DST]),
 113                                                        RTA_DATA(tb[RTA_DST]),
 114                                                        abuf, sizeof(abuf)));
 115                 }
 116         } else if (r->rtm_dst_len) {
 117                 fprintf(fp, "to 0/%d ", r->rtm_dst_len);
 118         }
 119
 120         if (r->rtm_tos) {
 121                 fprintf(fp, "tos %s ", rtnl_dsfield_n2a(r->rtm_tos, b1, sizeof(b1)));
 122         }
 123         if (tb[RTA_PROTOINFO]) {
 124                 fprintf(fp, "fwmark %#x ", *(uint32_t*)RTA_DATA(tb[RTA_PROTOINFO]));
 125         }
 126
 127         if (tb[RTA_IIF]) {
 128                 fprintf(fp, "iif %s ", (char*)RTA_DATA(tb[RTA_IIF]));
 129         }
 130
 131         if (r->rtm_table)
 132                 fprintf(fp, "lookup %s ", rtnl_rttable_n2a(r->rtm_table, b1, sizeof(b1)));
 133
 134         if (tb[RTA_FLOW]) {
 135                 uint32_t to = *(uint32_t*)RTA_DATA(tb[RTA_FLOW]);
 136                 uint32_t from = to>>16;
 137                 to &= 0xFFFF;
 138                 if (from) {
 139                         fprintf(fp, "realms %s/",
 140                                 rtnl_rtrealm_n2a(from, b1, sizeof(b1)));
 141                 }
 142                 fprintf(fp, "%s ",
 143                         rtnl_rtrealm_n2a(to, b1, sizeof(b1)));
 144         }
 145
 146         if (r->rtm_type == RTN_NAT) {
 147                 if (tb[RTA_GATEWAY]) {
 148                         fprintf(fp, "map-to %s ",
 149                                 format_host(r->rtm_family,
 150                                             RTA_PAYLOAD(tb[RTA_GATEWAY]),
 151                                             RTA_DATA(tb[RTA_GATEWAY]),
 152                                             abuf, sizeof(abuf)));
 153                 } else
 154                         fprintf(fp, "masquerade");
 155         } else if (r->rtm_type != RTN_UNICAST)
 156                 fprintf(fp, "%s", rtnl_rtntype_n2a(r->rtm_type, b1, sizeof(b1)));
 157
 158         fputc('\n', fp);
 159         fflush(fp);
 160         return 0;
 161 }
 162
 163 /* Return value becomes exitcode. It's okay to not return at all */
 164 static int iprule_list(int argc, char **argv)
 165 {
 166         struct rtnl_handle rth;
 167         int af = preferred_family;
 168
 169         if (af == AF_UNSPEC)
 170                 af = AF_INET;
 171
 172         if (argc > 0) {
 173                 //bb_error_msg("\"rule show\" needs no arguments");
 174                 bb_warn_ignoring_args(argc);
 175                 return -1;
 176         }
 177
 178         xrtnl_open(&rth);
 179
 180         xrtnl_wilddump_request(&rth, af, RTM_GETRULE);
 181         xrtnl_dump_filter(&rth, print_rule, stdout);
 182
 183         return 0;
 184 }
 185
 186
 187 /* Return value becomes exitcode. It's okay to not return at all */
 188 static int iprule_modify(int cmd, int argc, char **argv)
 189 {
 190         int table_ok = 0;
 191         struct rtnl_handle rth;
 192         struct {
 193                 struct nlmsghdr n;
 194                 struct rtmsg    r;
 195                 char            buf[1024];
 196         } req;
 197
 198         memset(&req, 0, sizeof(req));
 199
 200         req.n.nlmsg_type = cmd;
 201         req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
 202         req.n.nlmsg_flags = NLM_F_REQUEST;
 203         req.r.rtm_family = preferred_family;
 204         req.r.rtm_protocol = RTPROT_BOOT;
 205         req.r.rtm_scope = RT_SCOPE_UNIVERSE;
 206         req.r.rtm_table = 0;
 207         req.r.rtm_type = RTN_UNSPEC;
 208
 209         if (cmd == RTM_NEWRULE) {
 210                 req.n.nlmsg_flags |= NLM_F_CREATE|NLM_F_EXCL;
 211                 req.r.rtm_type = RTN_UNICAST;
 212         }
 213
 214         while (argc > 0) {
 215                 if (strcmp(*argv, "from") == 0) {
 216                         inet_prefix dst;
 217                         NEXT_ARG();
 218                         get_prefix(&dst, *argv, req.r.rtm_family);
 219                         req.r.rtm_src_len = dst.bitlen;
 220                         addattr_l(&req.n, sizeof(req), RTA_SRC, &dst.data, dst.bytelen);
 221                 } else if (strcmp(*argv, "to") == 0) {
 222                         inet_prefix dst;
 223                         NEXT_ARG();
 224                         get_prefix(&dst, *argv, req.r.rtm_family);
 225                         req.r.rtm_dst_len = dst.bitlen;
 226                         addattr_l(&req.n, sizeof(req), RTA_DST, &dst.data, dst.bytelen);
 227                 } else if (matches(*argv, "preference") == 0 ||
 228                            matches(*argv, "order") == 0 ||
 229                            matches(*argv, "priority") == 0) {
 230                         uint32_t pref;
 231                         NEXT_ARG();
 232                         if (get_u32(&pref, *argv, 0))
 233                                 invarg("preference value", *argv);
 234                         addattr32(&req.n, sizeof(req), RTA_PRIORITY, pref);
 235                 } else if (strcmp(*argv, "tos") == 0) {
 236                         uint32_t tos;
 237                         NEXT_ARG();
 238                         if (rtnl_dsfield_a2n(&tos, *argv))
 239                                 invarg("TOS value", *argv);
 240                         req.r.rtm_tos = tos;
 241                 } else if (strcmp(*argv, "fwmark") == 0) {
 242                         uint32_t fwmark;
 243                         NEXT_ARG();
 244                         if (get_u32(&fwmark, *argv, 0))
 245                                 invarg("fwmark value", *argv);
 246                         addattr32(&req.n, sizeof(req), RTA_PROTOINFO, fwmark);
 247                 } else if (matches(*argv, "realms") == 0) {
 248                         uint32_t realm;
 249                         NEXT_ARG();
 250                         if (get_rt_realms(&realm, *argv))
 251                                 invarg("realms", *argv);
 252                         addattr32(&req.n, sizeof(req), RTA_FLOW, realm);
 253                 } else if (matches(*argv, "table") == 0 ||
 254                            strcmp(*argv, "lookup") == 0) {
 255                         uint32_t tid;
 256                         NEXT_ARG();
 257                         if (rtnl_rttable_a2n(&tid, *argv))
 258                                 invarg("table ID", *argv);
 259                         req.r.rtm_table = tid;
 260                         table_ok = 1;
 261                 } else if (strcmp(*argv, "dev") == 0 ||
 262                            strcmp(*argv, "iif") == 0) {
 263                         NEXT_ARG();
 264                         addattr_l(&req.n, sizeof(req), RTA_IIF, *argv, strlen(*argv)+1);
 265                 } else if (strcmp(*argv, "nat") == 0 ||
 266                            matches(*argv, "map-to") == 0) {
 267                         NEXT_ARG();
 268                         addattr32(&req.n, sizeof(req), RTA_GATEWAY, get_addr32(*argv));
 269                         req.r.rtm_type = RTN_NAT;
 270                 } else {
 271                         int type;
 272
 273                         if (strcmp(*argv, "type") == 0) {
 274                                 NEXT_ARG();
 275                         }
 276                         if (matches(*argv, "help") == 0)
 277                                 bb_show_usage();
 278                         if (rtnl_rtntype_a2n(&type, *argv))
 279 // bogus-looking error message "invalid argument 'cannot parse rule type' to '<*argv>'"
 280                                 invarg("cannot parse rule type", *argv);
 281                         req.r.rtm_type = type;
 282                 }
 283                 argc--;
 284                 argv++;
 285         }
 286
 287         if (req.r.rtm_family == AF_UNSPEC)
 288                 req.r.rtm_family = AF_INET;
 289
 290         if (!table_ok && cmd == RTM_NEWRULE)
 291                 req.r.rtm_table = RT_TABLE_MAIN;
 292
 293         xrtnl_open(&rth);
 294
 295         if (rtnl_talk(&rth, &req.n, 0, 0, NULL, NULL, NULL) < 0)
 296                 return 2;
 297
 298         return 0;
 299 }
 300
 301 /* Return value becomes exitcode. It's okay to not return at all */
 302 int do_iprule(int argc, char **argv)
 303 {
 304         static const char * const ip_rule_commands[] =
 305                 {"add", "delete", "list", "show", 0};
 306         int cmd = 2; /* list */
 307
 308         if (argc < 1)
 309                 return iprule_list(0, NULL);
 310         if (*argv)
 311                 cmd = index_in_substr_array(ip_rule_commands, *argv);
 312
 313         switch (cmd) {
 314                 case 0: /* add */
 315                         cmd = RTM_NEWRULE;
 316                         break;
 317                 case 1: /* delete */
 318                         cmd = RTM_DELRULE;
 319                         break;
 320                 case 2: /* list */
 321                 case 3: /* show */
 322                         return iprule_list(argc-1, argv+1);
 323                         break;
 324                 default:
 325                         bb_error_msg_and_die("unknown command %s", *argv);
 326         }
 327         return iprule_modify(cmd, argc-1, argv+1);
 328 }